A pediatric client is admitted to the unit with failure to thrive. The mother states that the child has been "spitting up" and excessively crying immediately after every bottle. What diagnostic test will the nurse anticipate to confirm a diagnosis?

A. An upper gastrointestinal series is commonly used to diagnose gastroesophageal reflux (GER), which can cause symptoms like spitting up and crying after feedings, leading to failure to thrive. This test helps visualize the esophagus, stomach, and duodenum for abnormalities. B. A biopsy of the small intestine is typically done to diagnose celiac disease, which is less likely in this clinical scenario. C. An ultrasound is used to diagnose pyloric stenosis, which presents with projectile vomiting and is less consistent with the described symptoms. D. A lower gastrointestinal series is used to detect intestinal blockages, which are not suggested by the symptoms of spitting up and crying immediately after feeding.